I also asked my source why he thought so many Republicans had been supporting such an incredibly unpopular bill. He gave three reasons:
First off, there was what he referred to as the "Rovian School of thought," which says that passing this bill would capture the Hispanic vote for the GOP for decades to come.
Next up, there's the "Chamber of Commerce" vote. He says these Republicans were heavily influenced by business groups that want cheap labor no matter what the cost is for the rest of the country.
Then there was the last group, the smallest group in his opinion, who were willing to sign onto a terrible bill just so they could say they were part of a big reform that had bipartisan support.The Inside Story Of How The Senate Immigration Bill Died - Right Wing News (Conservative News and Views)